You guys had a great thread on this back in 2015, but thought I'd better start a new one.

I want to try the vinegar flush described by HG. I just have a couple of questions:

1) If I remove the thermostat (raw-water-cooled system) and fill up the jacket with vinegar, am I right in thinking that the jacket is a contained space, with no connection to the rest of the engine? Therefore if the hoses at the Y intake are lifted up high enough there will be no overflow even if the jacket is filled to the brim?

2) How far does the jacket extend? I gather it must run all the way to where the anode is. Does it also connect to the exhaust manifold? I've got loads of crud in there, but of course I'm nervous about the possibility of getting water in the engine. Are the water and exhaust sections of the manifold separate sealed spaces?

Last year when I opened the two drains there was a lot of crud, and I made the mistake of leaving the plugs out, with the result that I had trouble getting them to tighten sufficiently in the spring to seal the drains. Actually had to use an o ring on the manifold drain to get it to seal. Good news is they came out again no problem yesterday. This year I want to do the job properly!

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CS33 said..
You guys had a great thread on this back in 2015, but thought I'd better start a new one.

I want to try the vinegar flush described by HG. I just have a couple of questions:

1) If I remove the thermostat (raw-water-cooled system) and fill up the jacket with vinegar, am I right in thinking that the jacket is a contained space, with no connection to the rest of the engine? Therefore if the hoses at the Y intake are lifted up high enough there will be no overflow even if the jacket is filled to the brim?

2) How far does the jacket extend? I gather it must run all the way to where the anode is. Does it also connect to the exhaust manifold? I've got loads of crud in there, but of course I'm nervous about the possibility of getting water in the engine. Are the water and exhaust sections of the manifold separate sealed spaces?

Last year when I opened the two drains there was a lot of crud, and I made the mistake of leaving the plugs out, with the result that I had trouble getting them to tighten sufficiently in the spring to seal the drains. Actually had to use an o ring on the manifold drain to get it to seal. Good news is they came out again no problem yesterday. This year I want to do the job properly!

Vinegar is too weak to remove calcium build-up. Awhile back I did an experiment with seashells [just calcium] I put seashells in jars and tried vinegar in one, CLR in another and Metal Gleam in the third and watched the effect. The vinegar and CLR did very slowly dissolve the sea shells but the Metal Gleam was the clear winner! Metal Gleam is a phosphoric cleaning product made by Nowra chemicals and is widely used in the dairy and fishing industries. I would suggest you watch a few youtube videos by "Barnacle Buster" Barnacle buster is just a very expensive phosphoric acid mix sold to yachties at roughly 10 times the price of Metal gleam but their videos are extremely helpful.
I regularly clean my cooling system on my raw water cooled Volvo 7b. I simply disconnect the rubber hose after the intake pump and with a bit of hose extend the end to just above the height of the block. The other end where the water enters the exhaust I remove the hose and raise it to the same height and fix in place. Blow as much of the water out of the system then add an acid mixture and let sit for 20 minutes or so. Drop one end of the hose into a bucket and drain the foul-smelling crap out. Button it all back together and run the engine. I have made up a 12v pump and tank set up as shown in the barnacle buster videos but have not used it yet. I mix the metal gleam at 1:5 and the total mix is about a litre or so.
Disconnecting the hose where the raw water coolant normally enters the exhaust makes the cooling passages self-contained and nothing will enter the exhaust valves.

I used cleaning vinegar neat which is 8%. Same method as Ramona described on my raw water cooled DV10. Good result much better flow now

I did this job on my 10 hp Bukh. I used brick clean diluted to 50% strength ( about 15% acid ) filled the water chamber through the thermostat housing and left it for 24 hrs. When I drained it the water was green with dissolved salt and crud. I never had any more problems with overheating. Bukhs are all cast iron inside and take a bit of cleaning so don't pussyfoot around. At least that's my experience.

I think (not 100% sure) that Bukh cylinders have "wet" liners, which means there is a seal which is in contact with the cooling flow.
Whatever is used to flush, should ideally not harm that particular seal (and I guess any other seals). Manufacturers also warn about using the wrong lubricant on that seal, so if you are using anything aggressive best to make sure it doesn't harm/harden/swell such seals. Maybe test it in a jar for 24h and compare to a "control" seal held in plain water.

I use Metal gleam at 5:1 to wash down my deck and topsides. I don't wear gloves. Stings if you have cuts on your fingers. Only attacks rust and calcium, etches aluminium. I have left mixtures in old cast iron engine parts with various mixed metals and seals etc for days and found no problems. Vinegar would be safer still.
This bloke is using barnacle buster in an outboard with an alloy block!

Thanks everyone for your responses. I plan to try it this weekend!

I ran 7% vinegar through it twice, leaving it to sit for an hour and then flushing with water afterwards. Everything flowing out clean now. We'll see how it starts in the spring!

Thanks again for your help.

Paul

I am thinking about a raw water flush as my engine (new to me) has not been serviced for a long time.

I have managed to draw the anode bolt. No anode left at all. I now have the problem the new anode needs tapering as there must be a build up of crud just inside the plug access hole and it wont screw back in.

So I guess could do with some flushing.

I have read some on the 2015 thread and seems acetic acid/vinegar should be the starting point.

So how do I go about getting them vinegar in and then flushing through to get the crud out. Are there any drain plugs.

I saw mentioned removing the thermostat and housing, so I guess that is a way in. How do I get the crud out?

My main problem here is that I can't get the thermostat housing to move. The four vetical allen key bolts are solid and just won't move. Access is difficult to get any load on or heat. I have tried diesel on the rust but the bolts are very long so can't get lube down to the thread at the end.

Any suggestions my appreciated.

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joyful said..
I am thinking about a raw water flush as my engine (new to me) has not been serviced for a long time.

I have managed to draw the anode bolt. No anode left at all. I now have the problem the new anode needs tapering as there must be a build up of crud just inside the plug access hole and it wont screw back in.

So I guess could do with some flushing.

I have read some on the 2015 thread and seems acetic acid/vinegar should be the starting point.

So how do I go about getting them vinegar in and then flushing through to get the crud out. Are there any drain plugs.

I saw mentioned removing the thermostat and housing, so I guess that is a way in. How do I get the crud out?

My main problem here is that I can't get the thermostat housing to move. The four vetical allen key bolts are solid and just won't move. Access is difficult to get any load on or heat. I have tried diesel on the rust but the bolts are very long so can't get lube down to the thread at the end.

Any suggestions my appreciated.

What engine? Is this a raw water cooled engine with an anode or is the anode in the heat exchanger?

On the DV10 the anode is on the water jacket at the back of the engine. I had a problem with crud build up trapping the anode and used to put as big a drill bit as would fit through the hole to clear it for the new anode. I didn't power the bit, just pushed it through. I got fed up with this though and decided to de-gunk the engine hence the brick clean job. It really worked and I never had any more problems. The drain plug was on the right hand side looking from the front, low on the block.

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Ramona said..

joyful said..
I am thinking about a raw water flush as my engine (new to me) has not been serviced for a long time.

I have managed to draw the anode bolt. No anode left at all. I now have the problem the new anode needs tapering as there must be a build up of crud just inside the plug access hole and it wont screw back in.

So I guess could do with some flushing.

I have read some on the 2015 thread and seems acetic acid/vinegar should be the starting point.

So how do I go about getting them vinegar in and then flushing through to get the crud out. Are there any drain plugs.

I saw mentioned removing the thermostat and housing, so I guess that is a way in. How do I get the crud out?

My main problem here is that I can't get the thermostat housing to move. The four vetical allen key bolts are solid and just won't move. Access is difficult to get any load on or heat. I have tried diesel on the rust but the bolts are very long so can't get lube down to the thread at the end.

Any suggestions my appreciated.

What engine? Is this a raw water cooled engine with an anode or is the anode in the heat exchanger?

Its raw water cooled DV20. I will have a go at scraping away inside as well as filing down the anode to taper it.